A problem with light sources comprised of one or more solid-state light emitters (e.g., light emitting diodes) is that the intensity of light emitted by a solid-state light emitter is subject to change as a result of changes in its temperature and aging. Furthermore, the characteristics (and thus the light emitting capabilities) of solid-state light emitters may vary from batch to batch. As a result, in systems where the integrity of light emitted by a light source needs to be maintained (e.g., in display backlighting and illumination systems), some sort of system is needed to measure and regulate the light source's light.